U.S. patent application number 11/122368 was filed with the patent office on 2006-11-09 for seal arrangement for a fan-turbine rotor assembly.
This patent application is currently assigned to United Technologies Corporation. Invention is credited to Craig A. Nordeen, James W. Norris, Gary Roberge, Gabriel Suciu.
Application Number | 20060251508 11/122368 |
Document ID | / |
Family ID | 36731097 |
Filed Date | 2006-11-09 |
United States Patent
Application |
20060251508 |
Kind Code |
A1 |
Norris; James W. ; et
al. |
November 9, 2006 |
Seal arrangement for a fan-turbine rotor assembly
Abstract
A fan-turbine rotor hub includes an outer periphery scalloped by
a multitude of elongated openings. Each elongated opening defines
an inducer receipt section to receive an inducer section and a
hollow fan blade section. An inducer exit from each inducer section
is located adjacent a core airflow passage within each fan blade
section to provide communication therebetween. A seal is located
between an inner fan blade mount and a blade receipt section to
minimize airflow leakage between the inducer exit and the core
airflow passage.
Inventors: |
Norris; James W.; (Lebanon,
CT) ; Nordeen; Craig A.; (Manchester, CT) ;
Roberge; Gary; (Tolland, CT) ; Suciu; Gabriel;
(Glastonbury, CT) |
Correspondence
Address: |
CARLSON, GASKEY & OLDS, P.C.
400 WEST MAPLE ROAD
SUITE 350
BIRMINGHAM
MI
48009
US
|
Assignee: |
United Technologies
Corporation
|
Family ID: |
36731097 |
Appl. No.: |
11/122368 |
Filed: |
May 5, 2005 |
Current U.S.
Class: |
415/116 |
Current CPC
Class: |
F02C 3/073 20130101;
Y02T 50/672 20130101; Y02T 50/60 20130101; F02K 3/06 20130101; F01D
11/005 20130101; F02K 3/068 20130101 |
Class at
Publication: |
415/116 |
International
Class: |
F04D 31/00 20060101
F04D031/00 |
Claims
1. A fan assembly for a tip turbine engine comprising: a fan hub
defining an axis of rotation, said fan hub defining an elongated
opening with a blade receipt section located about an outer
periphery of said fan hub; a fan blade section having an inner fan
blade mount engageable with said blade receipt section to retain
said fan blade section to said fan hub, said fan blade section
defining a fan blade core airflow passage to receive airflow from
an inducer passage; and a seal mountable within each of said
elongated openings between said blade receipt section and said fan
blade mount.
2. The fan assembly as recited in claim 1, further comprising an
inducer section defining said inducer passage, said inducer section
receivable within said elongated opening such that said seal
contacts said inducer section and said fan blade mount.
3. The fan assembly as recited in claim 1, wherein said seal is
generally annular.
4. The fan assembly as recited in claim 3, wherein said seal is
oval.
5. The fan assembly as recited in claim 1, further comprising a tip
turbine mounted to said fan blade section.
6. The fan assembly as recited in claim 1, wherein said blade
receipt section includes a semi-cylindrical engagement.
7. A fan assembly for a tip turbine engine comprising: a fan hub
defining an axis of rotation, said fan hub defining an elongated
opening with a blade receipt section located about an outer
periphery of said fan hub; an inducer section at least partially
mounted within said elongated opening; a fan blade section having
an inner fan blade mount engageable with blade receipt section to
retain said fan blade section to said fan hub, said fan blade
section defining a fan blade core airflow passage to receive
airflow from an inducer passage; and a seal mountable within each
of said elongated openings to contact said inducer section, said
blade receipt section and said fan blade mount.
8. The fan hub as recited in claim 7, wherein said inducer section
includes an inducer exit, said inducer exit surrounded by said
seal.
9. The fan assembly as recited in claim 8, wherein said inner fan
blade mount includes a semi-cylindrical portion retained within
said blade receipt section, said semi-cylindrical portion located
adjacent said seal.
10. The fan hub as recited in claim 9, wherein said
semi-cylindrical portion defines axially non-symmetrical engagement
surface to provide a wedged engagement with said blade receipt
section.
11. A fan assembly for a tip turbine engine comprising: a fan hub
defining an axis of rotation, said fan hub defining an elongated
opening with a blade receipt section located about an outer
periphery of said fan hub, said elongated opening defining an
inducer passage; a fan blade section having an inner fan blade
mount engageable with blade receipt section to retain said fan
blade section to said fan hub, said fan blade section defining a
fan blade core airflow passage to receive airflow from an inducer
passage; and a seal mountable within each of said elongated
openings to contact said blade receipt section and said fan blade
mount to minimize airflow leakage between said inducer passage and
said core airflow passage.
12. The fan assembly as recited in claim 11, wherein said inner fan
blade mount includes a semi-cylindrical portion retained within
said blade receipt section, said semi-cylindrical portion located
adjacent said seal.
13. The fan hub as recited in claim 12, wherein said
semi-cylindrical portion defines axially non-symmetrical engagement
surface to provide a wedged engagement with said blade receipt
section.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a tip turbine engine, and
more particularly to a fan-turbine rotor assembly with a mechanical
retention and sealing arrangement between each of a multiple of
hollow fan blades.
[0002] An aircraft gas turbine engine of the conventional turbofan
type generally includes a forward bypass fan, a compressor, a
combustor, and an aft turbine all located along a common
longitudinal axis. A compressor and a turbine of the engine are
interconnected by a shaft. The compressor is rotatably driven to
compress air entering the combustor to a relatively high pressure.
This pressurized air is then mixed with fuel in a combustor and
ignited to form a high energy gas stream. The gas stream flows
axially aft to rotatably drive the turbine which rotatably drives
the compressor through the shaft. The gas stream is also
responsible for rotating the bypass fan. In some instances, there
are multiple shafts or spools. In such instances, there is a
separate turbine connected to a separate corresponding compressor
through each shaft. In most instances, the lowest pressure turbine
will drive the bypass fan.
[0003] Although highly efficient, conventional turbofan engines
operate in an axial flow relationship. The axial flow relationship
results in a relatively complicated elongated engine structure of
considerable longitudinal length relative to the engine diameter.
This elongated shape may complicate or prevent packaging of the
engine into particular applications.
[0004] A recent development in gas turbine engines is the tip
turbine engine. Tip turbine engines locate an axial compressor
forward of a bypass fan which includes hollow fan blades that
receive airflow from the axial compressor therethrough such that
the hollow fan blades operate as a centrifugal compressor.
Compressed core airflow from the hollow fan blades is mixed with
fuel in an annular combustor and ignited to form a high energy gas
stream which drives the turbine integrated onto the tips of the
hollow bypass fan blades for rotation therewith as generally
disclosed in U.S. Patent Application Publication Nos.: 20030192303;
20030192304; and 20040025490.
[0005] The tip turbine engine provides a thrust to weight ratio
equivalent to conventional turbofan engines of the same class
within a package of significantly shorter length.
[0006] One significant rotational component of a tip turbine engine
is the fan-turbine rotor assembly. The fan-turbine rotor assembly
includes components that rotate at relatively high speeds to
generate bypass airflow while communicating a core airflow through
each of the multitude of hollow fan blades. A large percentage of
the expense associated with a tip turbine engine is the manufacture
of the fan-turbine rotor assembly to minimize airflow loss through
each of the multitude of hollow fan blades.
[0007] Accordingly, it is desirable to provide an assembly
arrangement for a fan-turbine rotor assembly that is relatively
inexpensive to manufacture yet provides a high degree of
reliability and minimal airflow loss.
SUMMARY OF THE INVENTION
[0008] A fan-turbine rotor assembly for a tip turbine engine
according to the present invention includes a fan hub which has an
outer periphery scalloped by a multitude of elongated openings.
Each elongated opening defines an inducer receipt section to
receive an inducer section and a blade receipt section to retain a
hollow fan blade section. The blade receipt section retains each of
the hollow fan blade sections adjacent each inducer section. An
inner fan blade mount is located adjacent an inducer exit of each
inducer section to provide a core airflow communication path from
the inducer passages within each inducer section into the core
airflow passage within each fan blade section.
[0009] A seal is located between the inner fan blade mount and the
blade receipt section to minimize airflow leakage therebetween. The
seal also engages the inducer exit of each inducer section to
minimize leakage of airflow from the inducer section into the core
airflow passage of each hollow fan blade section and to accommodate
tolerance variations therebetween.
[0010] The present invention therefore provides an assembly
arrangement for a fan-turbine rotor assembly, which is relatively
inexpensive to manufacture yet provides a high degree of
reliability and minimal airflow loss.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The various features and advantages of this invention will
become apparent to those skilled in the art from the following
detailed description of the currently preferred embodiment. The
drawings that accompany the detailed description can be briefly
described as follows:
[0012] FIG. 1 is a partial sectional perspective view of a tip
turbine engine;
[0013] FIG. 2 is a longitudinal sectional view of a tip turbine
engine along an engine centerline;
[0014] FIG. 3 is an exploded view of a fan-turbine rotor
assembly;
[0015] FIG. 4 is an assembled view of a fan-turbine rotor
assembly;
[0016] FIG. 5 is an expanded perspective view of an inducer
section;
[0017] FIG. 6 is an expanded perspective view of the fan-turbine
rotor assembly;
[0018] FIG. 7A is an exploded view of a fan blade mounted within a
fan-turbine rotor assembly;
[0019] FIG. 7B is a partially fragmented view of a fan blade
mounted within a blade receipt section of the fan-turbine rotor
assembly of FIG. 7A;
[0020] FIG. 7C is a partial sectional view of a fan blade mounted
within a fan-turbine rotor assembly;
[0021] FIG. 7D is a rear sectional view of the engagement between
an inducer receipt section, a blade receipt section, an inducer
section and a fan blade section;
[0022] FIG. 8 is a top view of a seal for use with the blade mount
of the present invention;
[0023] FIG. 9A an exploded view of a fan blade mounted to a hub
with an integral inducer section of a fan-turbine rotor assembly;
and
[0024] FIG. 9B is a partially fragmented view of a fan blade
mounted within a blade receipt section of the fan-turbine rotor
assembly of FIG. 9A; and
[0025] FIG. 9C a partial sectional view of a fan blade mounted to a
hub with an integral inducer section of a fan-turbine rotor
assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0026] FIG. 1 illustrates a general perspective partial sectional
view of a tip turbine engine type gas turbine engine 10. The engine
10 includes an outer nacelle 12, a nonrotatable static outer
support structure 14 and a nonrotatable static inner support
structure 16. A multitude of fan inlet guide vanes 18 are mounted
between the static outer support structure 14 and the static inner
support structure 16. Each inlet guide vane preferably includes a
variable trailing edge 18A.
[0027] A nose cone 20 is preferably located along the engine
centerline A to smoothly direct airflow into an axial compressor 22
adjacent thereto. The axial compressor 22 is mounted about the
engine centerline A behind the nose cone 20.
[0028] A fan-turbine rotor assembly 24 is mounted for rotation
about the engine centerline A aft of the axial compressor 22. The
fan-turbine rotor assembly 24 includes a multitude of hollow fan
blades 28 to provide internal, centrifugal compression of the
compressed airflow from the axial compressor 22 for distribution to
an annular combustor 30 located within the nonrotatable static
outer support structure 14.
[0029] A turbine 32 includes a multitude of tip turbine blades 34
(two stages shown) which rotatably drive the hollow fan blades 28
relative to a multitude of tip turbine stators 36 which extend
radially inwardly from the static outer support structure 14. The
annular combustor 30 is axially forward of the turbine 32 and
communicates with the turbine 32.
[0030] Referring to FIG. 2, the nonrotatable static inner support
structure 16 includes a splitter 40, a static inner support housing
42 and an static outer support housing 44 located coaxial to said
engine centerline A.
[0031] The axial compressor 22 includes the axial compressor rotor
46 from which a plurality of compressor blades 52 extend radially
outwardly and a compressor case 50 fixedly mounted to the splitter
40. A plurality of compressor vanes 54 extend radially inwardly
from the compressor case 50 between stages of the compressor blades
52. The compressor blades 52 and compressor vanes 54 are arranged
circumferentially about the axial compressor rotor 46 in stages
(three stages of compressor blades 52 and compressor vanes 54 are
shown in this example). The axial compressor rotor 46 is mounted
for rotation upon the static inner support housing 42 through a
forward bearing assembly 68 and an aft bearing assembly 62.
[0032] The fan-turbine rotor assembly 24 includes a fan hub 64 that
supports a multitude of the hollow fan blades 28. Each fan blade 28
includes an inducer section 66, a hollow fan blade section 72 and a
diffuser section 74. The inducer section 66 receives airflow from
the axial compressor 22 generally parallel to the engine centerline
A and turns the airflow from an axial airflow direction toward a
radial airflow direction. The airflow is radially communicated
through a core airflow passage 80 within the fan blade section 72
where the airflow is centrifugally compressed. From the core
airflow passage 80, the airflow is turned and diffused toward an
axial airflow direction toward the annular combustor 30. Preferably
the airflow is diffused axially forward in the engine 10, however,
the airflow may alternatively be communicated in another
direction.
[0033] A gearbox assembly 90 aft of the fan-turbine rotor assembly
24 provides a speed increase between the fan-turbine rotor assembly
24 and the axial compressor 22. Alternatively, the gearbox assembly
90 could provide a speed decrease between the fan-turbine rotor
assembly 24 and the axial compressor rotor 46. The gearbox assembly
90 is mounted for rotation between the static inner support housing
42 and the static outer support housing 44. The gearbox assembly 90
includes a sun gear shaft 92 which rotates with the axial
compressor 22 and a planet carrier 94 which rotates with the
fan-turbine rotor assembly 24 to provide a speed differential
therebetween. The gearbox assembly 90 is preferably a planetary
gearbox that provides co-rotating or counter-rotating rotational
engagement between the fan-turbine rotor assembly 24 and an axial
compressor rotor 46. The gearbox assembly 90 is mounted for
rotation between the sun gear shaft 92 and the static outer support
housing 44 through a forward bearing 96 and a rear bearing 98. The
forward bearing 96 and the rear bearing 98 are both tapered roller
bearings and both handle radial loads. The forward bearing 96
handles the aft axial loads while the rear bearing 98 handles the
forward axial loads. The sun gear shaft 92 is rotationally engaged
with the axial compressor rotor 46 at a splined interconnection 100
or the like.
[0034] In operation, air enters the axial compressor 22, where it
is compressed by the three stages of the compressor blades 52 and
compressor vanes 54. The compressed air from the axial compressor
22 enters the inducer section 66 in a direction generally parallel
to the engine centerline A and is turned by the inducer section 66
radially outwardly through the core airflow passage 80 of the
hollow fan blades 28. The airflow is further compressed
centrifugally in the core airflow passage 80 of the hollow fan
blades 28 by rotation of the hollow fan blades 28. From the core
airflow passage 80, the airflow is turned and diffused axially
forward in the engine 10 into the annular combustor 30. The
compressed core airflow from the hollow fan blades 28 is mixed with
fuel in the annular combustor 30 and ignited to form a high-energy
gas stream. The high-energy gas stream is expanded over the
multitude of tip turbine blades 34 mounted about the outer
periphery of the fan blades 28 to drive the fan-turbine rotor
assembly 24, which in turn drives the axial compressor 22 through
the gearbox assembly 90. Concurrent therewith, the fan-turbine
rotor assembly 24 discharges fan bypass air axially aft to merge
with the core airflow from the turbine 32 in an exhaust case 106. A
multitude of exit guide vanes 108 are located between the static
outer support housing 44 and the nonrotatable static outer support
structure 14 to guide the combined airflow out of the engine 10 to
provide forward thrust. An exhaust mixer 110 mixes the airflow from
the turbine blades 34 with the bypass airflow through the fan
blades 28.
[0035] Referring to FIG. 3, the fan-turbine rotor assembly 24 is
illustrated in an exploded view. The fan hub 64 is the primary
structural support of the fan-turbine rotor assembly 24 (FIG. 4).
The fan hub 64 is preferably forged and then milled to provide the
desired geometry. The fan hub 64 defines a bore 111 and an outer
periphery 112. The outer periphery 112 is preferably scalloped by a
multitude of elongated openings 114 located about the outer
periphery 112. The elongated openings 114 extend into a fan hub web
115.
[0036] Each elongated opening 114 defines an inducer receipt
section 117 to receive each inducer section 66. The inducer receipt
section 117 generally follows the shape of the inducer section 66.
That is, the inducer receipt section 117 receives the more
complicated shape of the inducer section 66 without the necessity
of milling the more complicated shape directly into the fan hub
64.
[0037] The inducer sections 66 are essentially conduits that define
an inducer passage 118 between an inducer inlet 120 and an inducer
exit 126 (also illustrated in FIG. 5). Preferably, the inducer
sections 66 are formed of a composite material.
[0038] The inducer sections 66 together form an inducer 116 of the
fan-turbine rotor assembly 24. The inducer inlet 120 of each
inducer passage 118 extends forward of the fan hub 64 and is canted
toward a rotational direction of the fan hub 64 such that inducer
inlet 120 operates as an air scoop during rotation of the
fan-turbine rotor assembly 24 (FIG. 6). Each inducer passage 118
provides separate airflow communication to each core airflow
passage 80 when each fan blade section 72 is mounted within each
elongated opening 114.
[0039] Inducer sections 66 are preferably uni-directionally
assembled into the fan hub 64 from the front such that the forces
exerted upon the fan-turbine rotor assembly 24 during operation
correspond with further locking of the inducer sections 66 into the
fan hub 64. Each inducer inlet 120 preferably at least partially
overlaps the next inducer inlet 120 when assembled into the fan hub
64 (FIG. 6) through the overlapped orientation the inducer inlets
120 lock the inducer sections 66 into the fan hub 64. That is,
operational forces maintain the inducer sections 66 within the fan
hub 64 in an assembled condition rather than operating to
disassemble the components. Alternatively, or in addition the
inducer sections 66 may be mounted to the fan hub 64 through an
attachment such as bonding, welding, rivets, threaded fasteners,
and the like.
[0040] Referring to FIG. 6, the fan hub 64 retains each hollow fan
blade section 72 within each elongated opening 114 through a blade
receipt section 122. The blade receipt section 122 preferably forms
an axial semi-cylindrical opening 125 (also illustrated in FIGS. 7A
and 7B) formed along the axial length of the elongated openings
114. It should be understood that other retention structures will
likewise be usable with the present invention.
[0041] Referring to FIG. 7A, each hollow fan blade section 72
includes an inner fan blade mount 124 that corresponds with the
blade receipt section 122 to retain the hollow fan blade section 72
within the fan hub 64 (FIG. 7B). The inner fan blade mount 124
preferably includes a semi-cylindrical portion 127 to radially
retain the fan blade 28 through a dove-tail, fir-tree, or bulb-type
engagement structure. The fan hub 64 supports the hoop load
required to retain the integrity of the disk/blade structure.
[0042] The inner fan blade mount 124 is preferably
uni-directionally mounted into the blade receipt section 122 from
the rear face of the fan hub 64. The inner fan blade mount 124
engages the blade receipt section 122 during operation of the
fan-turbine rotor assembly 24 to provide a directional lock
therebetween. That is, the inner fan blade mount 124 and the blade
receipt section 122 may be frustoconical or axially non-symmetrical
such that the forward segments 124a, 127a form a smaller engagement
surface than the rear segment 124b, 127b to provide a wedged
engagement therebetween when assembled.
[0043] A seal 131 is preferably located between the inner fan blade
mount 124 and the blade receipt section 122 to minimize airflow
leakage therebetween. The seal 131 (also illustrated in FIG. 8) is
generally annular in shape and is preferably manufactured of a thin
metal or an elastomer such as Fluro-silicone rubber depending on
the expected temperature. It should be understood that various seal
shapes may be utilized with the present invention.
[0044] Referring to FIG. 7C, each inducer section 66 is retained
within the fan hub 64 by interaction with the inner fan blade mount
124. That is, the inner fan blade mount 124 engages the inducer
exit 126 (FIG. 5) to further retain the inducer sections 66 into
the fan hub 64 to provide core airflow communication through the
inducer passages 118 and into the core airflow passage 80.
[0045] The seal 131 engage the inducer exit 126 of each inducer
section 66 to further minimize leakage of airflow from the inducer
section 66 into core the airflow passage 80 each hollow fan blade
section 72. That is, the seal 131 is in contact with the inducer
exit 126, the inner fan blade mount 124 and the blade receipt
section 122 to accommodate tolerance variations therebetween and
provide a generally air-tight engagement therebetween.
[0046] Referring to FIG. 9A, the fan hub 64' itself forms the
multitude of inducer sections 66. Each inducer section 66' formed
by the fan hub 64' is essentially a conduit that defines an inducer
passage 118' between an inducer inlet section 120' and an inducer
exit section 126' which communicates with a blade receipt section
122' as generally described above.
[0047] A seal 131' need only seal the blade receipt section 122'
formed into the fan hub 64' with the fan blade mount 124' (also
illustrated in FIG. 9B). That is, as the inducer section 66' is
integral with the fan hub 64', the potential for airflow leakage is
minimized.
[0048] It should be understood that relative positional terms such
as "forward," "aft," "upper," "lower," "above," "below," and the
like are with reference to the normal operational attitude of the
vehicle and should not be considered otherwise limiting.
[0049] The foregoing description is exemplary rather than defined
by the limitations within. Many modifications and variations of the
present invention are possible in light of the above teachings. The
preferred embodiments of this invention have been disclosed,
however, one of ordinary skill in the art would recognize that
certain modifications would come within the scope of this
invention. It is, therefore, to be understood that within the scope
of the appended claims, the invention may be practiced otherwise
than as specifically described. For that reason the following
claims should be studied to determine the true scope and content of
this invention.
* * * * *